How does one dyno a ram air accurately? : Yamaha R1 Forum

keep-up · 03-01-2003, 08:44 AM

Someone help me out here. Without semi-accurate and dynamic airflow (dynamic meaning as the drive wheels speed increase so does the airflow) during a dyno run how can you even come close to estimating the HP gains from ram air or even supercharging for that matter?

The more important question is: when you have your fuel injection map properly tuned on a dyno using a PCIIIr for example won't your engine run leaner at speed (out on the road) due to the increase in air volume? Does this not increase the risk of burning up valves and other things? In other words, even though the fuel map is properly tuned for a dyno run, with ram air at speed out on the road won't the system run leaner?

SCARY!!!

keep-up · 03-01-2003, 09:01 AM

||| bump |||

martinc · 03-01-2003, 09:13 AM

Well,you cant really just go on a dyno-session and map it;

You got to collect loads of infos with the box installed,on the road/track with lambda sensors,on-board data-gathering devices and move one of the sensor on the box as well(the one under the seat).....

Then you also have to understand what to make of the data.

Only a handfull of race teams and Graves has those software/hardware...and the knowledge.

Those that have the HBR boxes should get the Graves maps and as an option,the slides stops.(optional!)

I"ll have those maps soon on my site.(already have the one with the stops)right after I get Chuck"s permission!

Sam Farris · 03-01-2003, 09:16 AM

In my opinion, you don't.
Here is a re-post of something I wrote on the YZF-R1 Forum

Ram air – does it work?

Absolutely!

It has been featured and has worked successfully on numerous bikes from Kawasaki, Honda, Suzuki, etc.

With that said, does that mean that if I put a ram-air box on my non ram-air bike that I should expect to see the same kind of results as a ‘factory’ ram air bike?

In my opinion ,…. don’t count on it.

A factory ram-air system has numerous sub-systems, both mechanical/pneumatic and electrical/electronic that keep the air-fuel ratio exactly where it should be throughout the operating range of both engine speed and ground velocity. How did the manufacturers accomplish this? Through numerous tests and trial runs in both wind tunnels and road testing with bikes that are bristling with sensors such as airbox pressure, exhaust oxygen, throttle position, air temperature, etc., etc., that are working in conjunction with a multi-channel data acquisition system. This data is analyzed, which then may precipitate changes to the various parameters of airbox volume/geometry, fuel delivery/mapping, in addition to adjustments and/or the elimination/addition of the previously mentioned sub-systems. A lot of detailed engineering goes into these bikes to make them run as smoothly as they do.

We, on the other hand (the majority of us anyway), do not have access to, or would even know where to begin with the process of instrumenting our bike and analyzing the data. We find ourselves in the position of using a ram-air box designed by a motorcycle racing team for their specific racing motorcycle. What we then have to do is install the ram-air and verify that it is operating properly (sealed and mounted). This is just the beginning. Next we need to determine if the air-fuel ratio is correct throughout the operating range of both engine speed and ground velocity. How do we do this without a portable multi-gas analyzer? Well, you don’t, so you use your seat-of-the-pants dyno. The problem with this is that human perception, along with many other variables, make it difficult, at best, to perform a repeatable evaluation.

Let’s say we do get a handle, somehow, on the air-fuel mix throughout the operating range of both engine speed and ground velocity. Now what? What is the next direction to go in regard to correcting it? With carbs you can play with jetting, slide springs, jet-needle taper, float level, low-speed mixture screw, etc. Aside from the decision as to what to adjust and by how much comes the trial & error associated with changing one thing at a time and a seat-of-the-pants dyno run between each change. Granted, with an EFI system this is much easier due to the reduction in fuel delivery variables, but even with this, there is still the issue of ground velocity induced fuel-air mix variability due to ram-air induced airbox pressurization.

This is where the factory sub-systems come into play.

These systems compensate for the airbox pressurization so as to keep the air-fuel ratio exactly where it should be throughout the operating range of both engine speed and ground velocity. The home-brewed shade tree mechanic has none of this available to him in his ‘box of tools’.

My point here is that the aftermarket fitment of a ram-air system onto a non ram-air bike is a long and tedious process of trial & error tweaking. In the end, it still does not possess the ultimate power and smooth throttle transition and fuel-delivery refinement that a ‘factory’ ram-air bike will have.

If you are OK with this, then an aftermarket ram-airbox may be ‘just the ticket’ in the endless pursuit of ‘free’ horsepower.

Sam

martinc · 03-01-2003, 09:22 AM

I got to agree on the "tedious" part...lol

Its the fitment of a highly accurate air/fuel sensor on my bike that got me the jetting I have on my carburreted ramaired bike.

Given the fact that now we have EFI and PC3"s,given the fact that Graves uses sensors and data-gathering devices on the roads and track,given the fact that they did numerous runs to get as optimal a map that they could,me think,without any disrespect my dear sam that it would be time for you non-beleivers to change your song!

And that is a fact!

Big Daddy · 03-01-2003, 09:34 AM

One particular tool thats available to all of us(albeit a costly one) is the Lambda Sensor (MartinC must have this) which does in fact monitor the air/fuel mix @ a given RPM / Speed while being ridden. Its certainly not the be all end all to this equation but its far more than not having it at all.

BD

turnone · 03-01-2003, 09:39 AM

WEll I must say that with all the "TESTING" that these factories do then why did it ever end up that when an aftermarket company put some sensors on the early ram air GIXXERS, they found that the design of their inlet ports were a shape and size that it created a negative pressure as to suck out the port while moving forward?
I would think with all that testing that it would have been found and cured long before production.
That is why on the early model gixxers youd see duct tape over the outer part of the inlet ports.

AS the mere mortals that we are opening and operating aftermarket companies. I guess no one would ever be as smart as the people who design and build stuff for Factory Yamaha or Honda.
I guess the guys they have working for them carry a much more extensive knowledge then anyone else in the world. They gain a higher power that help them in designing and building a superior product.
I am presumming that thes very inteligent people are found not a single place then the factories as no aftermarket company could ever find a crew so knowledgeable or inteeligent to design or capitalize on a companies engineering.

I gues that why the facoties often seek the help of other companies to help design their products. ANYONE in the motorcycle industry knows that the factories pay other people to do alot of their research. They cannot handle one off parts of equipent very well and often farm these things out to the mortal community that we are next to the factories. T=Until the products make it to huge scale then the factories start to make alot of the parts themselves....

I guess until then we will ahve to rely on a company like Suzuki to make us a Ram air box, that NEVER worked. Because no one can put out a product that is as good or better then the factories

martinc · 03-01-2003, 10:22 AM

Quote:

Originally posted by Big Daddy
One particular tool thats available to all of us(albeit a costly one) is the Lambda Sensor (MartinC must have this) which does in fact monitor the air/fuel mix @ a given RPM / Speed while being ridden. Its certainly not the be all end all to this equation but its far more than not having it at all.

BD

yes,Bosch sensor and highly accurate (to 1 millivolt)digital gauge.

if you can reach .900mv at full throttle,you"re smack on the money;

if you see .750/.800/.850 (cycling) while cruising,you"re again right on the money...and guess what.....yep,I do see those figures

this place also sells on-board EGT.

turnone · 03-01-2003, 11:23 AM

Quote:

Originally posted by martinc
yes,Bosch sensor and highly accurate (to 1 millivolt)digital gauge.

if you can reach .900mv at full throttle,you"re smack on the money;

if you see .750/.800/.850 (cycling) while cruising,you"re again right on the money...and guess what.....yep,I do see those figures

this place also sells on-board EGT.

I have an onboard egt that i have been thinking about using on my bike. It is used on lseds for jetting but i am thinking about putting it on my R1, i wonder how it would work

Sam Farris · 03-01-2003, 12:43 PM

Martin,

Granted, I concede that lambda sensors and associated readouts gives one a much better handle on the air-fuel mix throughout the operating range of both engine speed and ground velocity. Also a pre-generated EFI map brings one closer to that ideal with less tinkering that with carbs. But it is still all an approximation made better with tinkering. My position is that if you expect your bike to run as smoothly as a factory ram-air, then you will be disappointed. I have never said it can’t be done or it does not work, because all other things being equal, there are many non-factory ram-air bikes that will walk away from my non-ram air bike up at the higher ground speeds. By the same token, those same bikes will not have the same silky smooth carburetion (excuse the term) throughout the rev band my bike does.

Turnone,

I did not specify who all is involved in the development of the factory ram-air systems, just that they work well. Your Suzuki story, if factual in it’s content, is the exception rather than the rule. Understand that when I question the factuality of your story, I am not questioning your integrity.

What I don’t understand is why people tend to gravitate to the exception, rather than the rule when they argue a point. Don’t they realize that it takes away from their point, rather than support it?

In addition, my target audience was the regular shade-tree mechanic (which I consider myself), wishing to improve his/her streetbike, and not a factory race team. Factory race teams do quite well when designing these systems for themselves. Bear in mind their target is for a race bike (6,000 RPM+), not a street bike.

It was not my intent to insult your intelligence or your mechanical aptitude.

JG,

You like selecting these ‘hot’ topics and then sit back and watch, don’t cha’?

Are you trying to top your ‘counter-steering’ topic post record ?

Sam

martinc · 03-01-2003, 12:51 PM

Quote:

Originally posted by turnone
I have an onboard egt that i have been thinking about using on my bike. It is used on lseds for jetting but i am thinking about putting it on my R1, i wonder how it would work

Those are less than accurate;the one using leds give rough(really rough)read-outs.....if you are looking into something much more accurate,let me know.(digital read-out with actual numbers)

yamaguy · 03-01-2003, 03:29 PM

The hp gain rule of thumb for "ram-aired" bikes is 3-4%, ask any top level tuner and they will tell you that. Where that figure came from exactly I don't know, but after you hear it a few times you accept it as fact. Possibly it came from testing for high level racing (Formula 1) or even the aircraft industry.

While air box pressure in a ram type box is minimal what is important is that the engine is drawing from a cooler air source than what it would if it were rearward facing or even frontward facing but restricted (current R1s). Cooler air on any given day means more air density and thus more horsepower per cylinder charge assuming the carburetion is not extremely lean.

As far as damaging your engine, think of it like this, you would not recarburet if you were going for a ride on a cool morning, but your engine will make more power if it was running a little fat at normal air temperatures. Even if you were running extremely lean, your engine would simply not produce enough revs to raise combustion temperatures high enough to cause engine damage, it would just stop producing power.

Too much is made of the "ram-air" issue, but make no mistake it does work. Any airbox that is larger and can draw from a cooler air source will make more power than one that does not, assuming the carburetion has been compensated for. That's why all "ram-aired" bikes stock or aftermarket make more power than comparable bikes that are not.

turnone · 03-01-2003, 07:25 PM

Quote:

Originally posted by martinc
Those are less than accurate;the one using leds give rough(really rough)read-outs.....if you are looking into something much more accurate,let me know.(digital read-out with actual numbers)

I did not mean leds i meant sleds, as in snow sleds...

Mine is a digital readout out one that can read two different cylinders at a time...

I think it will work on the bike as well.....

One think i am not sur eis what temp should the exhaust on are bieks be at? you tune a sled by exhaust gas temperatures....

Sam Farris · 03-01-2003, 07:43 PM

Quote:

Originally posted by turnone
...One think i am not sur eis what temp should the exhaust on are bieks be at? you tune a sled by exhaust gas temperatures....

On our bikes you will want a lambda sensor (oxygen sensor) plumbed into the exhaust circuit. These are designed to operate at around 600 C (1112 F), but should not be exposed to greater than 850 C (1562 F). This means that their position in the exhaust circuit is critical. The output signal from the sensor is a pulse and the ratio of the 'on' time of the pulse in respect to the 'off' time is depedent upon the oxygen level in the exhaust. At the stoichiometry mixture level, the ratio of 'on' time to 'off' time is 1 to 1.

Sam

martinc · 03-01-2003, 07:50 PM

oups,my bad........

yeah,it would be better to have 4 EGT sensors,but the dash would then look like what?

My bike probably.......

lol

turnone · 03-01-2003, 08:55 PM

Quote:

Originally posted by Sam Farris
On our bikes you will want a lambda sensor (oxygen sensor) plumbed into the exhaust circuit. These are designed to operate at around 600 C (1112 F), but should not be exposed to greater than 850 C (1562 F). This means that their position in the exhaust circuit is critical. The output signal from the sensor is a pulse and the ratio of the 'on' time of the pulse in respect to the 'off' time is depedent upon the oxygen level in the exhaust. At the stoichiometry mixture level, the ratio of 'on' time to 'off' time is 1 to 1.

Sam

hmm thats wierd, i know the position is critical as on two stroke motors doing sleds...

but the temps are identical for two stroke sleds and dirt bikes two are bikes..
A sled is running great between 1200 and 1350 degrees.. any hoter and its lean and going o seize, any colder and shes choking wih to much fuel....
Id have though tthe one or the other to be hotter then that or colder...

keep-up · 03-01-2003, 09:03 PM

Quote:

Originally posted by Sam Farris

JG,

You like selecting these ‘hot’ topics and then sit back and watch, don’t cha’? Are you trying to top your ‘counter-steering’ topic post record ?

Sam

Good one Sam! Of course not. But there are much more experience folks than myself on topics like these. Of course I had no idea my countersteer thread would turn out like it did. I had to step away from the box for a few hours but I've got my own comments to add shortly. Things mentioned so far make sense to me on both sides of the arguement.

Yamaguy,

Your comment about not needing to recarbuerate early in the morning is a good one. Unfortunately, I don't have the experience to know how much air temperature and localized pressure (inside the air box) will affect the air-fuel mixture ratios. I certainly hope your comments are accurate. I have no doubt that ram air will increase the power. The basis for my original question is "at what cost?" In other words, will this leaner mixture wear the engine faster or perhaps even damage it?

Another thought. A fuel mapping device like a PCIII only adjusts by engine speed but does not have a clue about ground velocity. You could optimize the map throughout the RPM range for 6th gear (maxing at 180 mph ground velocity) or for 6th gear on a dyno at 0 mph ground velocity BUT NOT BOTH!!!!!! Wouldn't you need additional telemetry even on a factory ram-air bike to optimize at all engine speeds and ground velocities. In other words, a PCIII does a good job of controlling fuel mixtures based on engine speed. Wouldn't you need another gizmo to work in concert to control fuel mixtures based on ground velocities. And then the whole mess starts to get convoluted.

Sounds like an EXCELLENT engineering college senior design project for a Feedback Control class!

Keep 'em coming!

keep-up · 03-01-2003, 09:06 PM

Quote:

Originally posted by turnone
hmm thats wierd, i know the position is critical as on two stroke motors doing sleds...

but the temps are identical for two stroke sleds and dirt bikes two are bikes..
A sled is running great between 1200 and 1350 degrees.. any hoter and its lean and going o seize, any colder and shes choking wih to much fuel....
Id have though tthe one or the other to be hotter then that or colder...

Deven, you need to give me one of those beers! Your typing is seriously suffering!!!

Dan Kyle · 03-01-2003, 09:12 PM

I have not read all the posts so I will try and keep this short.
The fuel injected bikes do compensate for ram air, all of them have a pressure sensor in the airbox so as the speed and pressure increase the fuel mixture is adjusted.
But that is not really why I am posting.
Within a few months Dynojet will have a device that plugs into a Power Commander and with the addition of a lambda sensor will record air fuel ratio as well as RPM, and throttle position. This will allow the user to look after a ride, or race, and see if any mods to the map are needed, and where they are needed.

keep-up · 03-01-2003, 09:18 PM

Quote:

Originally posted by keep-up
Wouldn't you need another gizmo to work in concert to control fuel mixtures based on ground velocities. And then the whole mess starts to get convoluted.

Correction: Wouldn't you need another gizmo to work in concert to control fuel mixtures based on air box pressure, not ground velocity. A head wind vs. a tail wind could change this scenario quickly.